Hydraulically released inflation tool for permanent bridge plug

ABSTRACT

Various embodiments of an improved downhole disconnect tool are provided, some of which may include a first housing releasably connected to a second housing, a first piston releasably connected to the first housing, and a second piston releasably connected to the second housing. Various fluid communication ports and ball seats may be provided in various combinations in the first and second pistons and in the second housing to enable remote control of the tool by circulating one or more balls into engagement with one or more of the ball seats to disconnect the first housing from the second housing, and thereby disconnect any structures connected to the first and second housings, respectively. Other features and aspects of the invention are also provided.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to subsurface well equipment and, moreparticularly, to an apparatus for remotely disconnecting downhole welltools and/or conduits from one another.

2. Description of the Related Art

The present invention was developed in response to a problem that existswith the current manner in which an inflatable packer located downholeis remotely disconnected from a production tubing, such as a coiledtubing, to which the packer is connected, such as in a permanent bridgeplug application. One current approach to remotely disconnecting thepacker from the tubing is through a mechanical release joint that isdisposed between the packer and the tubing. The mechanical release jointconsists generally of two tubular members, one of which is partiallydisposed within the other. The tubular members are connected to oneanother by shear screws. One tubular member is connected to the tubing,and the other is connected to the packer. The mechanical release jointis designed such that when it is desired to disconnect the tubing fromthe packer, a force of sufficient magnitude is applied to the tubing sothat the shear screws will shear, thus disconnecting the two tubularmembers of the mechanical release joint, and thereby also disconnectingthe tubing from the packer. One problem with this type of mechanicalrelease joint, however, is that it may be unintentionally actuated byunforeseen downhole conditions, such as pressure or flow rate variationsthat are sufficiently large to shear the shear screws. As such, thepresent invention was developed to provide an improved release jointthat is not prone to being unintentionally actuated by unforeseendownhole conditions.

SUMMARY OF THE INVENTION

In one aspect, the invention may be a disconnect tool for use in asubterranean well, comprising: a first housing releasably connected to asecond housing, the second housing having a circulation port and aninner bore therethrough; a first piston releasably connected to thefirst housing, and having an inner bore therethrough and an upper ballseat; and a second piston releasably connected to the second housing andhaving an inner bore therethrough and a lower ball seat, the lower ballseat having a diameter less than a diameter of the upper ball seat, thesecond piston having a run-in circulation port, an inflation port, and asecondary circulation port, the run-in circulation port being in fluidcommunication with the circulation port in the second housing before alower ball is engaged with the lower ball seat, the inflation portdirecting fluid flow from the inner bore of the first piston to aportion of the inner bore of the second housing below the lower ballseat when the lower ball is engaged with the lower ball seat, and thesecondary circulation port being in fluid communication with thecirculation port in the second housing after the second piston isdisconnected from the second housing, the first piston beingdisconnected from the first housing after an upper ball is engaged withthe upper ball seat to thereby disconnect the first housing from thesecond housing. Another feature of this aspect of the invention may bethat the first housing may further include a lower extension includingat least one locking member adapted for releasable engagement with alocking groove in the second housing, and the first piston includes anouter recess disposed to receive the at least one locking member afterthe first piston has been disconnected from the first housing. Anotherfeature of this aspect of the invention may be that the first piston isdisposed to maintain engagement of the at least one locking member withthe locking groove before the first piston is disconnected from thefirst housing. Another feature of this aspect of the invention may bethat the second piston is releasably connected to the second housing byat least one shear screw designed to shear at a force corresponding to amaximum setting pressure of a packer to which the tool is connected.Another feature of this aspect of the invention may be that the run-incirculation port is disposed below the lower ball seat. Another featureof this aspect of the invention may be that the inflation port isdisposed above the lower ball seat. Another feature of this aspect ofthe invention may be that the secondary circulation port is disposedbetween the run-in circulation port and the inflation port. Anotherfeature of this aspect of the invention may be that the inflation portis disposed between the lower ball seat and the secondary circulationport. Another feature of this aspect of the invention may be that thesecond housing may further include a fluid passageway establishing fluidcommunication between the inflation port and the inner bore of thesecond housing below the lower ball seat. Another feature of this aspectof the invention may be that the second housing may further include atleast one closure member having an open and a closed position, andadapted to restrict fluid flow through the inner bore of the secondhousing when in its closed position and permit fluid flow through theinner bore of the second housing when in its open position. Anotherfeature of this aspect of the invention may be that the second pistonmay further include an inflation reentry port disposed below the lowerball seat, and a stopper is sealingly disposed within the second housingto direct fluid flow through the inflation reentry port into the innerbore of the second piston. Another feature of this aspect of theinvention may be that the tool may further include an orifice plugengaged with an orifice in the second piston establishing fluidcommunication between the inflation port and the circulation port in thesecond housing.

In another aspect, the present invention may be a disconnect tool foruse in a subterranean well, comprising: a first housing releasablyconnected to a second housing, the second housing having a first fluidcirculation port, a second circulation port, and an inner boretherethrough; a first piston releasably connected to the first housing,and having an inner bore therethrough, an upper ball seat and a lowerball seat, the lower ball seat having a diameter less than a diameter ofthe upper ball seat, the first piston having a run-in circulation portand an inflation port, the run-in circulation port being in fluidcommunication with the first circulation port in the second housingbefore a lower ball is engaged with the lower ball seat, the inflationport directing fluid flow from the inner bore of the first piston to aportion of the inner bore of the second housing below the lower ballseat when the lower ball is engaged with the lower ball seat; and asecond piston releasably connected to the second housing, the inflationport being in fluid communication with the second circulation port inthe second housing after the second piston is disconnected from thesecond housing, the first piston being disconnected from the firsthousing after a second ball is engaged with the upper ball seat tothereby disconnect the first housing from the second housing. Anotherfeature of this aspect of the invention may be that the tool may furtherinclude an orifice plug engaged with an orifice in the second pistonestablishing fluid communication between the inflation port and thecirculation port in the second housing. Another feature of this aspectof the invention may be that the first housing may further include alower extension including at least one locking member adapted forreleasable engagement with a locking groove in the second housing, andthe first piston includes an outer recess disposed to receive the atleast one locking member after the first piston has been disconnectedfrom the first housing. Another feature of this aspect of the inventionmay be that the first piston is disposed to maintain engagement of theat least one locking member with the locking groove before the firstpiston is disconnected from the first housing. Another feature of thisaspect of the invention may be that the second piston is releasablyconnected to the second housing by at least one shear screw designed toshear at a force corresponding to a maximum setting pressure of a packerto which the tool is connected. Another feature of this aspect of theinvention may be that the second housing may further include at leastone closure member having an open and a closed position, and adapted torestrict fluid flow through an inner bore of the second housing when inits closed position and permit fluid flow through the inner bore of thesecond housing when in its open position.

In yet another aspect, the present invention may be a disconnect toolfor use in a subterranean well, comprising: a first housing releasablyconnected to a second housing, the second housing having a circulationport and an inner bore therethrough; a first piston releasably connectedto the first housing, and having an inner bore therethrough and an upperball seat; a second piston releasably connected to the second housingand having a run-in circulation port in fluid communication with thecirculation port in the second housing before the second piston isdisconnected from the second housing, and a secondary circulation portin fluid communication with the circulation port in the second housingafter the second piston is disconnected from the second housing, thefirst piston being disconnected from the first housing after an upperball is engaged with the upper ball seat to thereby disconnect the firsthousing from the second housing; and an orifice plug engaged with therun-in circulation port. Another feature of this aspect of the inventionmay be that the first housing may further include a lower extensionincluding at least one locking member adapted for releasable engagementwith a locking groove in the second housing, and the first pistonincludes an outer recess disposed to receive the at least one lockingmember after the first piston has been disconnected from the firsthousing. Another feature of this aspect of the invention may be that thefirst piston is disposed to maintain engagement of the at least onelocking member with the locking groove before the first piston isdisconnected from the first housing. Another feature of this aspect ofthe invention may be that the second piston is releasably connected tothe second housing by at least one shear screw designed to shear at aforce corresponding to a maximum setting pressure of a packer to whichthe tool is connected.

Another feature of this aspect of the invention may be that the secondhousing may further include at least one closure member having an openand a closed position, and adapted to restrict fluid flow through aninner bore of the second housing when in its closed position and permitfluid flow through the inner bore of the second housing when in its openposition.

In still another aspect, the present invention may be a disconnect toolfor use in a subterranean well, comprising: a first housing releasablyconnected to a second housing, the second housing having a firstcirculation port, a second circulation port, and an inner boretherethrough; an orifice plug engaged with the first circulation port; afirst piston releasably connected to the first housing, and having aninner bore therethrough, an upper ball seat, and a run-in circulationport establishing fluid communication between the inner bore of thefirst piston and the first circulation port; and a second pistonreleasably connected to the second housing, the run-in circulation portbeing in fluid communication with the second circulation port after thesecond piston is disconnected from the second housing, the first pistonbeing disconnected from the first housing after an upper ball is engagedwith the upper ball seat to thereby disconnect the first housing fromthe second housing. Another feature of this aspect of the invention maybe that the first housing may further include a lower extensionincluding at least one locking member adapted for releasable engagementwith a locking groove in the second housing, and the first pistonincludes an outer recess disposed to receive the at least one lockingmember after the first piston has been disconnected from the firsthousing. Another feature of this aspect of the invention may be that thefirst piston is disposed to maintain engagement of the at least onelocking member with the locking groove before the first piston isdisconnected from the first housing. Another feature of this aspect ofthe invention may be that the second piston is releasably connected tothe second housing by at least one shear screw designed to shear at aforce corresponding to a maximum setting pressure of a packer to whichthe tool is connected. Another feature of this aspect of the inventionmay be that the second housing may further include at least one closuremember having an open and a closed position, and adapted to restrictfluid flow through the inner bore of the second housing when in itsclosed position and permit fluid flow through the inner bore of thesecond housing when in its open position. Another feature of this aspectof the invention may be that the second piston is sealably disposedbetween the second housing and the first piston. Another feature of thisaspect of the invention may be that the tool may further include asecondary inflation piston releasably connected to the second housing byat least one shear screw designed to shear at a force corresponding to apressure less than a maximum setting pressure of a packer to which thetool is connected, fluid communication between the run-in circulationport and the first circulation port being restricted after the secondaryinflation piston is disconnected from the second housing, and fluidcommunication between the run-in circulation port and the secondcirculation port being established after the second piston isdisconnected from the second housing. Another feature of this aspect ofthe invention may be that the tool may further include a nut having aone-way ratchet mechanism adapted to allow movement of the secondaryinflation piston in only one direction. Another feature of this aspectof the invention may be that the tool may further include a springdisposed between a lower support shoulder on the second housing and thesecondary inflation piston.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side cross-sectional view of a first embodiment of theimproved release tool of the present invention.

FIG. 2 is a side cross-sectional view of a second embodiment of theimproved release tool of the present invention.

FIG. 2A is a cross-sectional view taken along line 2A—2A of FIG. 2.

FIG. 3 is a side cross-sectional view of a third embodiment of theimproved release tool of the present invention.

FIG. 4 is a side cross-sectional view of a fourth embodiment of theimproved release tool of the present invention.

FIG. 4A is a cross-sectional view taken along line 4A—4A of FIG. 4.

FIG. 5 is a side cross-sectional view of a fifth embodiment of theimproved release tool of the present invention.

FIG. 6 is a side cross-sectional view of a sixth embodiment of theimproved release tool of the present invention.

FIG. 7 is a side cross-sectional view of a seventh embodiment of theimproved release tool of the present invention.

FIG. 8 is a side cross-sectional view of an eighth embodiment of theimproved release tool of the present invention.

While the invention will be described in connection with the preferredembodiments, it will be understood that it is not intended to limit theinvention to those embodiments. On the contrary, it is intended to coverall alternatives, modifications, and equivalents as may be includedwithin the scope of the invention as defined by the appended claims.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

In the description that follows, like or similar parts are markedthrough the specification and drawings with the same reference numerals,respectively. The figures are not necessarily drawn to scale, and insome instances, have been exaggerated or simplified to clarify certainfeatures of the invention. One skilled in the art will appreciate manydiffering applications of the described apparatus.

Referring to FIG. 1, a first embodiment of the improved release tool 10of the present invention is shown in a run-in position, prior to beingactuated. In this embodiment, the tool 10 includes a first, or upper,housing 12 that is releasably connected to a second, or lower, housing14. The upper housing 12 is adapted for connection to a production orcoiled tubing or perhaps another tool (not shown), and the lower housing14 is shown connected to a packer 15, only an upper portion of which isshown. In a specific embodiment, the lower housing 14 may comprise anupper member (or fish neck housing) 14 a and a lower member 14 b. Theupper housing 12 may include a lower extension 12 a that is disposedwithin the lower housing 14. The lower extension 12 a may include atleast one locking member or dog 12 b adapted for releasable engagementwith a locking groove 16 in the lower housing 14. As will be more fullyexplained below, the lower extension 12 a is designed to flex inwardly,away from the lower housing 14, such that the one or more locking dogs12 b will disengage from the locking groove 16 when the dogs 12 b arenot being held in engagement with the groove 16.

The tool 10 further includes a first, or release, piston 18 that isshown partially disposed within the upper housing 12 and partiallydisposed within the lower housing 14. The release piston 18 includes aninner bore 20 having a first, or upper, ball seat 22 adapted forengagement with an upper ball 24 (shown in phantom), the purpose ofwhich will be explained below. The release piston 18 is releasablyconnected to the upper housing 12 by at least one shear screw 26. Alower portion 18 a of the release piston 18 is disposed to hold thelocking dogs 12 b on the upper housing 12 in engagement with the lockinggroove 16 on the lower housing 14 when the tool 10 is in its run-inposition. The release piston 18 further includes an outer recess 28 forreceiving the locking dogs 12 b when the tool 10 is being actuated, aswill be further discussed below. Other aspects of the release piston 18will be described below when describing the operation of the tool 10.

The tool 10 further includes a second, or inflation, piston 30 disposedbelow the release piston 18 and within the lower housing 14. Theinflation piston 30 includes an inner bore 32 having a second, or lower,ball seat 34 adapted for engagement with a lower ball 36 (shown inphantom), the purpose of which will be explained below. The diameter ofthe lower ball seat 34 is less than the diameter of the upper ball seat22. The inflation piston 30 is releasably connected to the lower housing14 by at least one shear screw 38, which is designed to shear at apredetermined force corresponding to a preselected maximum settingpressure for the packer 15. The inflation piston 30 includes at leastone run-in circulation port 40 disposed below the lower ball seat 34(i.e., between the lower ball seat 34 and a lower end 30 a of theinflation piston 30). When the tool 10 is in its run-in position, asshown, the run-in circulation ports 40 are generally aligned and influid communication with corresponding circulation ports 42 in the lowerhousing 14. The inflation piston 30 further includes at least oneinflation port 44 above the lower ball seat 34 (i.e., between the lowerball seat 34 and an upper end 30 b of the piston 30). The at least oneinflation port 44 is adapted to direct fluid flow from the inner bore 20of the release piston 18 to a portion of an inner bore 17 of the lowerhousing 14 below the lower ball seat 34 when the lower ball 36 isengaged with the lower ball seat 34. The inflation piston 30 furtherincludes at least one secondary circulation port 46 disposed between thelower ball seat 34 and the at least one inflation port 44. The lowerhousing 14 includes at least one fluid passageway 48 through which fluidmay flow from the inner bore 32 of the inflation piston 30 and theinflation ports 44 down through the inner bore 17 to the packer 15, aswill be more fully discussed hereinbelow. The lower end 30 a of theinflation piston 30 is sealably disposed within a bottom stopper 50 thatis connected to the lower housing 14. The inflation piston 30 may alsoinclude a sleeve section 52 disposed through a flapper check valveassembly or cartridge 54 of the type known to those of skill in the art.In a specific embodiment, the assembly 54 may include an upper closuremember 56 (e.g., a flapper) and a lower closure member 58, each shown intheir closed positions in dashed lines. The inflation piston 30 may alsoinclude a locking nut 57 connected to the upper end 30 b of the piston30, the purpose of which will be explained below.

In operation, the tool 10 is run into a well (not shown) to its settingdepth, and fluid is pumped down the tubing (not shown), into the tool 10and circulated through the run-in circulation ports 40 in the inflationpiston 30 and out through the circulation ports 42 in the lower housing14. The lower ball 36 is placed into the fluid stream and pumped intoengagement with the lower ball seat 34. This will restrict circulatingfluid flow through ports 40 and 42, and will divert fluid flow throughthe inflation ports 44 and the fluid passageways 48 down to theinflatable packer 15. Fluid pressure will build up to set the packer 15.This is done in this embodiment using the bull head inflation method, aswill be understood by those of skill in the art. When the predeterminedmaximum setting pressure of the packer 15 is reached, the shear screws38 connecting the inflation piston 30 to the lower housing 14 willshear, thereby disconnecting the inflation piston 30 from the lowerhousing 14. The inflation piston 30 will then move downwardly by a firstdistance D1 until a shoulder 60 on the piston 30 engages a ledge 62 onthe lower housing 14. This will bring the secondary circulation ports 46on the inflation piston 30 into fluid communication with the circulationports 42 in the lower housing 14, and again permit fluid circulationfrom the earth's surface through the tool 10, and cause the pressure todrop in the tubing (not shown).

Having again established fluid circulation through the tool 10, fluidcan be produced to the earth's surface from the well until it is desiredto actuate the tool 10 to disconnect the tubing from the packer 15. Atthat time, the upper ball 24 (which is larger than the lower ball 36) isplaced into the fluid stream and pumped downhole into engagement withthe upper ball seat 22. Pressure is allowed to build up until shearscrews 26 shear, thereby disconnecting the release piston 18 from theupper housing 12. The release piston 18 will then move downwardly by asecond distance D2 until a shoulder 64 on the release piston 18 engagesa ledge 66 on the upper housing 12. It is preferred that the firstdistance D1 is greater than the second distance D2 so that there will besome space between the lower end of the release piston 18 and the upperend 30 b of the inflation piston 30 after both the release piston 18 andthe inflation piston 30 have been shifted downwardly to their respectivereleased positions (not shown). When the release piston 18 is shifteddownwardly to its released position, the outer recess 28 on the releasepiston 18 will be positioned adjacent the locking dogs 12 b on the upperhousing 12, and the locking dogs 12 b will be inwardly flexed into theouter recess 28, thereby disengaging the upper housing 12 from the lowerhousing 14. This also disconnects the tubing (not shown) from the packer15.

The tubing (not shown) may now be removed from the well (not shown) bypulling upwardly thereon. This will pull the upper housing 12, whichwill engage the ledge 66 of the upper housing 12 on the shoulder 64 ofthe release piston 18, and thereby cause upward movement of the releasepiston 18. This will cause a ledge 68 on the inner bore 20 of therelease piston 18 to engage a shoulder 70 on the locking nut 57, andthereby cause upward movement of the inflation piston 30. As theinflation piston 30 is pulled upwardly, the sleeve section 52 of theinflation piston 30 will pass through the flapper assembly 54 so thatthe lower flapper 58 will rotate upwardly to its closed position (shownin dashed lines) and the upper flapper 56 will rotate downwardly to itsclosed position (also shown in dashed lines). This will prevent anyfluid or contaminants from migrating down into the packer 15. The upperhousing 12, release piston 18 and inflation piston 30 may then be pulledto the surface, leaving the packer 15 and lower housing 14 in the well.If it is desired to extract the packer 15 to the surface, a grippingtool of the type known to those in the art (not shown) may be loweredinto the well and engaged with the locking groove 16 on the lowerhousing 14. Once engaged, the gripping tool may then pull the lowerhousing 14 and packer 15 to the earth's surface in a known manner.

A second embodiment of the present invention is shown in FIGS. 2 and 2A.The second embodiment is similar to the first embodiment shown inFIG. 1. The main differences between the first and second embodimentsare in the structure of the inflation piston 30 and lower housing 14. Inthe second embodiment, the inflation ports 44′ in the inflation piston30 are disposed in a generally longitudinal direction, whereas in thefirst embodiment the inflation ports 44 are disposed in a generallytransverse direction. The longitudinal inflation ports 44′ take theplace of the fluid passageways 48 in the lower housing 14 in the firstembodiment shown in FIG. 1. Also, in the second embodiment, thelongitudinal inflation ports 44′ are disposed between the lower ballseat 34 and the secondary circulation ports 46, whereas in the firstembodiment the secondary circulation ports 46 are disposed between thelower ball seat 34 and the inflation ports 44. Another difference isthat the second embodiment may also include a filter 80 disposed withinthe inflation piston 30 above the lower ball seat 34 to preventcontaminants from flowing into the ports 44′ or 46.

The operation of the second embodiment is very similar to that of thefirst embodiment. The tool 10 is run into the hole to its setting depthand fluid circulation is established through the ports 40 and 42. Thelower ball 36 is then dropped into engagement with the lower ball seat34, and fluid flow is diverted through the inflation ports 44′ toinflate the packer 15. When the packer 15 reaches its maximum pressure,the shear screws 38 will shear and the piston 30 will move downwardlyinto its released position, at which time the secondary circulationports 46 will be in fluid communication with the circulation ports 42,thereby permitting fluid circulation through the tool 10. To disconnectfrom the packer 15, the upper ball 24 is dropped into engagement withthe upper ball seat 22, and pressure is allowed to build up until theshear screws 26 are sheared. The release piston 18 then moves down andthe locking dogs 12 b retract into the outer recess 28, therebydisengaging the upper housing 12 from the lower housing 14. The upperhousing 12, release piston 18 and inflation piston 30 may then be pulledto the surface. A gripping tool may also be used to pull the lowerhousing 14 and packer 15 to the surface, if so desired, in the mannerexplained above.

A third embodiment of the present invention is shown in FIG. 3. Thethird embodiment is similar to the second embodiment shown in FIG. 2.The main differences between the second and third embodiments are in thestructure of the inflation piston 30 and the structure and position ofthe stopper 50. With reference to FIG. 3, the inflation piston 30includes at least one inflation reentry port 45 disposed below the lowerball seat 34 (i.e., between the lower ball seat 34 and the lower end 30a of the inflation piston 30). After the lower ball 36 has been dropped,fluid flow is diverted through the inflation ports 44′ and then backinto the inner bore 32 of the inflation piston 30 through the at leastone inflation reentry port 45, and then to the packer 15. The otherdifference between the second and third embodiments is that in the thirdembodiment the stopper 50′ includes an inner seal member 82 and an outerseal shoulder 84. When in the run-in position, as shown, the inner sealmember 82 is disposed above the at least one inflation reentry port 45for sealable engagement with the inner bore 32 of the inflation piston30, and the outer seal shoulder 84 is disposed below the at least oneinflation reentry port 45 for sealable engagement between the lowerhousing 14 and the inflation piston 30. It will be understood that theinner seal member 82 and outer seal shoulder 84 cooperate to provide asealed flow path to direct inflation fluids under pressure down to thepacker 15 for inflation of same. The operation of this third embodimentis as explained above for the second embodiment.

A fourth embodiment of the present invention is shown in FIGS. 4 and 4A,which is similar to the third embodiment shown in FIG. 3. The keydifference between the two is that the fourth embodiment employs anorifice plug method of inflating the packer 15 whereas the thirdembodiment employs the bull plug inflation method. As shown in FIG. 4,in the fourth embodiment, the inflation piston 30 includes an orifice 86for each longitudinal inflation port 44′ that establishes fluidcommunication between the corresponding longitudinal inflation port 44′and the circulation ports 42 in the lower housing 14. By providing theorifices 86, some of the fluid flowing through the inflation ports 44′to set the packer 15 is allowed to escape through the orifices 86 andthe circulation ports 42 in the lower housing 14. The amount of fluidthat is allowed to escape through the orifices 86 may be controlled byengaging an orifice plug 88 with each orifice 86 in a known manner. Thesize of the orifice plug 88 may be varied depending on the desiredmaximum inflation pressure of the packer 15. This provides foradditional control over the inflation of the packer 15. Other than thesedifferences, the operation of this fourth embodiment is as explainedabove for the third embodiment.

A fifth embodiment of the present invention is shown in FIG. 5, whichincludes an upper housing 12 and a lower housing 14 generally asdescribed above in connection with FIGS. 1–4. The fifth embodiment alsoincludes a release piston 18′, the structure of which is similar in somerespects and different in others in comparison to the release piston 18as described in FIGS. 1–4. The release piston 18′ as shown in FIG. 5also includes certain features of the inflation piston 30 shown in FIGS.1–4. As shown in FIG. 5, the release piston 18′ is connected to theupper housing 12 by shear screws 26, and includes an inner bore 20, andan outer recess 28 for receiving the locking dogs 12 b. The releasepiston 18′ also includes a circulation port 90 that establishes fluidcommunication between the inner bore 20 and the circulation ports 42(which may also be referred to as first circulation ports) in the lowerhousing 14, when the tool 10 of this fifth embodiment is in its run-inposition, as shown in FIG. 5. The release piston 18′ further includes agenerally longitudinal inflation port 92 establishing fluidcommunication from the inner bore 20 above a lower ball seat 93 to anexterior of the release piston 18′ at a point below the lower ball seat94. The release piston 18′ may further include an orifice 94establishing fluid communication between the inflation port 92 and thecirculation ports 42 in the lower housing 14. An orifice plug 96 may beengaged with the orifice 94. The function, structure and operation ofthe orifice 94 and orifice plug 96 are as explained above in connectionwith FIG. 4. This fifth embodiment further includes an inflation piston98 secured by shear screws 100 to the lower housing 14. The inflationpiston 98 includes an inner bore 102 through which a sleeve member 104of the release piston 18′ is disposed when the tool 10 is in its run-inposition, as shown. The inflation piston 98 also includes a shoulder 106adapted to stop against a ledge 108 on the lower housing 14. A plugmember 110 may be attached to the lower housing 14 and provided with astem 112 adapted for sealable engagement with a lower end of the innerbore 20 of the release piston 18′. This fifth embodiment may alsoinclude a flapper assembly 54 as described and illustrated above.

In operation, the fifth embodiment of the tool 10 is run into the wellin its run-in position as shown in FIG. 5, and fluid circulation isestablished through the inner bore 20, the circulation port 90, and thecirculation ports 42 in the lower housing 14. A lower ball (not shown)is then dropped into engagement with the lower ball seat 93. Thisdiverts fluid flow into the inflation passageway 92, some of whichescapes through the orifice 94 and the remainder of which continuesdownwardly through an annulus between the sleeve member 104 of therelease piston 18′ and the inner bore 102 of the inflation piston 98,and on down to inflate the packer 15. When the maximum inflationpressure of the packer 15 is reached, the shear screws 100 will shearand the inflation piston 98 will move downwardly until the shoulder 106comes to rest against the ledge 108. This will result in a pressuredrop, and will establish a fluid flow path out of the tool 10 throughone or more second circulation ports 114 in the lower housing 14, whichmay be disposed below the first circulation ports 42 in the lowerhousing. This will again permit fluid circulation through the tool 10,and, when it desired to disconnect from the packer 15, an upper ball(not shown) may then be dropped into engagement with the upper ball seat22. This will cause pressure to build up above the release piston 18′,which pressure will eventually shear the shear screws 26 and move therelease piston 18′ downwardly until shoulder 64 comes to rest againstthe ledge 66. This will result in the locking dogs 12 b retracting intothe outer recess 28, thereby disconnecting the upper housing 12 from thelower housing 14, in the manner as explained above in connection withthe other embodiments. The upper housing 12 may then be pulled to thesurface, which will also pull the release piston 18′ to the surface. Thelower housing 14, inflation piston 98 and packer 15 will remain in thewell. If it is desired to remove these components, an appropriate welltool (not shown) may be used to latch into the profile 16 at the top ofthe lower housing 14 to pull these remaining components to the surfacein a known manner.

A sixth embodiment of the present invention is shown in FIG. 6. Thissixth embodiment has an upper housing 12, a lower housing 14 and arelease piston 18, similar to those shown in FIGS. 1–4. The structure ofthe inflation piston 30 in this embodiment is different than in FIGS.1–4, and this embodiment does not use a lower ball, but, instead, onlythe upper ball. The inflation piston 30 is connected to the lowerhousing 14 by shear screws 38. The run-in circulation ports 40 on thepiston 30 are in fluid communication with the circulation ports 42 inthe lower housing when the tool 10 is in its run-in position, as shown.In a preferred embodiment, an orifice plug 116 is disposed in eachrun-in circulation port 40. The inflation piston 30 also includessecondary circulation ports 46 disposed between the run-in circulationports 40 and the upper end 30 b of the piston 30.

In operation, the sixth embodiment is run into the well (not shown) toits setting depth and pressurized fluid is pumped down to the packer 15to set it using the orifice inflation method. Note that it is notnecessary in this sixth embodiment to drop a lower ball, as wasexplained in connection with the above embodiments. As described above,using the orifice inflation method, some of the fluid will escape fromthe tool 10 through the run-in circulation ports 40, which are partiallyblocked by the orifice plugs 116, and the remainder of the fluid willflow down to the packer 15 to set it. When the maximum packer inflationpressure is reached, the shear screws 38 will shear and the piston 30will move downwardly until a shoulder 118 on the piston 30 comes to restagainst a ledge 120 on the lower housing 14. This will result in thesecondary circulation ports 46 moving into alignment with thecirculation ports 42 in the lower housing 14, and thereby again enablefluid circulation through the tool 10. This will allow the upper ball(not shown) to be dropped into engagement with the upper ball seat 22when it is desired to disconnect the tubing (not shown) from the packer15. Dropping the upper ball (not shown) will result in the shear screws26 shearing and downward movement of the release piston 18 to disconnectthe upper housing 12 from the lower housing 14, as more fully explainedabove in connection with the other embodiments.

A seventh embodiment of the present invention is shown in FIG. 7. Thisseventh embodiment has an upper housing 12 and a lower housing 14,similar to those shown in FIGS. 1–4. This seventh embodiment alsoincludes a release piston 18″ similar to the release pistons shown inFIGS. 1–4, except that the release piston 18″ further includes a lowerextension member 122 that extends through the flapper assembly 54 and issealably engaged with a lower bore 124 of the lower housing 14. Therelease piston 18″ further includes at least one run-in circulation port126 that may be located adjacent and in fluid communication with thecirculation ports 42 in the lower housing 14 when the tool 10 is in itsrun-in position, as shown. In this embodiment, an orifice plug 128 isengagingly disposed in each of the circulation ports 42 in the lowerhousing 14. This embodiment further includes an inflation piston 130releasably secured by shear pins 132 to the lower housing 14, andsealably disposed between the lower housing 14 and the release piston18″. The lower housing 14 also includes at least one secondarycirculation port 134 disposed below the circulation ports 42 in thelower housing 14.

In operation, the tool 10 is run into the hole to its setting depth, andfluid is pumped downhole to set the packer 15 using the orificeinflation method. Some of the fluid will escape through the run-incirculation ports 126 in the release piston 18″ and the circulationports 42, which are partially blocked by the orifice plugs 128, and theremainder of the fluid will flow further downhole to set the packer 15.When the packer 15 reaches its maximum setting pressure, the shearscrews 132 will shear and the inflation piston 130 will move downwardlyto establish a fluid flow path between the circulation ports 126 in therelease piston 18″ and the secondary circulation ports 134 in the lowerhousing 14. This will allow fluid circulation again, and when desired,the upper ball (not shown) can be dropped into engagement with the upperball seat 22 to disconnect the tubing (not shown) and upper housing 12from the lower housing 14 and packer 15, in the same manner as discussedabove. It is noted that, in this seventh embodiment, due to the use ofthe orifice inflation method, it is not necessary to drop a lower ballin order to set the packer 15.

An eighth embodiment of the present invention is shown in FIG. 8. Thiseighth embodiment is similar to the seventh embodiment, but includesadditional components in the area between the inflation piston 130(referred to below as the primary inflation piston) and the run-incirculation ports 126 on the release piston 18″. These additionalcomponents, as described below, are sometimes generally referred to as“Circulate Inflate Orifice Tool” (CIOT) components, and may include: asecondary inflation piston 136 connected to the lower housing 14 byshear screws 138 and having an inner bore 140 through which the lowerextension member 122 of the release piston 18″ may be disposed; a nut142 including a one-way ratchet mechanism and disposed about a lowerportion of the secondary inflation piston 136; a lock member 144disposed about a lower portion of the secondary inflation member 136between the nut 142 and a locking shoulder 146 on the inner bore of thelower housing 14; a spring 148 disposed within the lower housing 14around the lower extension member 122 and between the secondaryinflation piston 136 and a lower support shoulder 150 on the lowerhousing 14; and an upper support shoulder 152 on the lower housing 14above the secondary inflation piston 136. In a specific embodiment, theupper support shoulder 152 may comprise a snap ring disposed in aretaining groove in the lower housing 14.

For reasons that will become clear below, the shear screws 138 thatsecure the secondary inflation piston 136 to the lower housing 14 aredesigned to shear at a force corresponding to a pressure less than thepredetermined maximum packer setting pressure. For example, in aspecific embodiment, the designed shear pressure for the shear screws138 may be 600 p.s.i. and the predetermined maximum packer settingpressure may be 1,000 p.s.i. It is noted that the designed shearpressure corresponding to the shear screws 132 that secure the primaryinflation piston 130 to the lower housing 14 would be 1,000 p.s.i inthis specific embodiment.

In operation, after the tool 10 is run into the hole to its settingdepth, fluid may be pumped into the tool 10 to set the packer 15. Someof the fluid will pass through the run-in circulation ports 126 in therelease piston 18″ and either escape around the orifice plugs 128 andthrough the circulation ports 42, or act on and apply downward pressureto the secondary inflation piston 136. The remainder of the fluid willflow down through the inner bore 20 of the release piston 18″ to inflatethe packer 15, in the same manner as explained above with regard to theorifice inflation method. When the pressure acting on the packer 15reaches the designed shear pressure for the shear screws 138, thoseshear screws 138 will shear and the secondary inflation piston 136 willbe forced upwardly by the spring 148 until it comes to rest against theupper support shoulder 152. The pumping operation may be temporarilyceased at this point. When the secondary inflation piston 136 has beenmoved to this uppermost position, an annular seal 154 on the secondaryinflation piston 136 will be positioned above the circulation ports 42to thereby prevent fluid flow from the run-in circulation ports 128 outof the tool 10 through the circulation ports 42. The one-way ratchetmechanism of the nut 142 prevents the secondary inflation piston 136from moving back in a downward direction.

Continued pumping of fluid to the packer 15—this time under the bullhead inflation method since the circulation ports 42 with the orificeplugs 128 are now blocked, and all of the fluid will be acting on top ofthe inflation piston 130—will result in the shear screws 132 shearingwhen the maximum packer setting pressure is reached. This will allow theprimary inflation piston 130 to move down to open up a fluid flow pathbetween the run-in circulation ports 126 in the release piston 18″ andthe secondary circulation ports 134 in the lower housing 14. An upperball (not shown) may then be dropped into engagement with the upper ballseat 22 to release the release piston 18″ and allow the upper housing 12and the release piston 18″ to be retracted to the earth's surface in thesame manner as explained above. The CIOT components and the primaryinflation piston 130 are left in the well with the lower housing 14 andthe packer 15, all of which may be removed to the earth's surface ifdesired in the same manner explained above for the other embodiments.

From the above description it can be seen that the tool 10 of thepresent invention in its various embodiments has many advantages and canbe used for a variety of different purposes, including allowingcirculation while the packer 15 is being run into the well, inflatingthe packer 15, providing feedback when the packer 15 reaches its maximuminflation pressure, and allowing circulation of a ball to release thetool 10 in order to leave the packer 15 downhole. Further, the tool 10is not subject to being unintentionally actuated by unforeseenvariations in downhole conditions, as is the case with currentmechanical release joints.

Whereas the present invention has been described in particular relationto the drawings attached hereto, it should be understood that other andfurther modifications, apart from those shown or suggested herein, maybe made within the scope of the present invention. Accordingly, theinvention is therefore to be limited only by the scope of the appendedclaims.

1. A disconnect tool for use in a subterranean well, comprising: a firsthousing releasably connected to a second housing, the second housinghaving a circulation port and an inner bore therethrough; a first pistonreleasably connected to the first housing, and having an inner boretherethrough and an upper ball seat; and a second piston releasablyconnected to the second housing and having an inner bore therethroughand a lower ball seat, the lower ball seat having a diameter less than adiameter of the upper ball seat, the second piston having a run-incirculation port, an inflation port, and a secondary circulation port,the run-in circulation port being in fluid communication with thecirculation port in the second housing before a lower ball is engagedwith the lower ball seat, the inflation port directing fluid flow fromthe inner bore of the first piston to a portion of the inner bore of thesecond housing below the lower ball seat when the lower ball is engagedwith the lower ball seat, and the secondary circulation port being influid communication with the circulation port in the second housingafter the second piston is disconnected from the second housing, thefirst piston being disconnected from the first housing after an upperball is engaged with the upper ball seat to thereby disconnect the firsthousing from the second housing.
 2. The disconnect tool of claim 1,wherein the first housing further includes a lower extension includingat least one locking member adapted for releasable engagement with alocking groove in the second housing, and the first piston includes anouter recess disposed to receive the at least one locking member afterthe first piston has been disconnected from the first housing.
 3. Thedisconnect tool of claim 2, wherein the first piston is disposed tomaintain engagement of the at least one locking member with the lockinggroove before the first piston is disconnected from the first housing.4. The disconnect tool of claim 1, wherein the second piston isreleasably connected to the second housing by at least one shear screwdesigned to shear at a force corresponding to a maximum setting pressureof a packer to which the tool is connected.
 5. The disconnect tool ofclaim 1, wherein the run-in circulation port is disposed below the lowerball seat.
 6. The disconnect tool of claim 1, wherein the inflation portis disposed above the lower ball seat.
 7. The disconnect tool of claim1, wherein the secondary circulation port is disposed between the run-incirculation port and the inflation port.
 8. The disconnect tool of claim1, wherein the inflation port is disposed between the lower ball seatand the secondary circulation port.
 9. The disconnect tool of claim 1,wherein the second housing further includes a fluid passagewayestablishing fluid communication between the inflation port and theinner bore of the second housing below the lower ball seat.
 10. Thedisconnect tool of claim 1, wherein the second housing further includesat least one closure member having an open and a closed position, andadapted to restrict fluid flow through the inner bore of the secondhousing when in its closed position and permit fluid flow through theinner bore of the second housing when in its open position.
 11. Thedisconnect tool of claim 1, wherein the second piston further includesan inflation reentry port disposed below the lower ball seat, and astopper is sealingly disposed within the second housing to direct fluidflow through the inflation reentry port into the inner bore of thesecond piston.
 12. The disconnect tool of claim 1, further including anorifice plug engaged with an orifice in the second piston establishingfluid communication between the inflation port and the circulation portin the second housing.